[PATCH 08/30] path-walk: allow visiting tags

["Derrick Stolee via GitGitGadget" <gitgitgadget@gmail.com>]

From: Derrick Stolee <stolee@gmail.com>

In anticipation of using the path-walk API to analyze tags or include
them in a pack-file, add the ability to walk the tags that were included
in the revision walk.

Signed-off-by: Derrick Stolee <stolee@gmail.com>
---
 path-walk.c | 58 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 path-walk.h |  1 +
 2 files changed, 59 insertions(+)

diff --git a/path-walk.c b/path-walk.c
index d70e6840fb5..65f9856afa2 100644
--- a/path-walk.c
+++ b/path-walk.c
@@ -14,6 +14,7 @@
 #include "revision.h"
 #include "string-list.h"
 #include "strmap.h"
+#include "tag.h"
 #include "trace2.h"
 #include "tree.h"
 #include "tree-walk.h"
@@ -215,6 +216,9 @@ int walk_objects_by_path(struct path_walk_info *info)
 		.paths_to_lists = STRMAP_INIT
 	};
 
+	struct oid_array tagged_tree_list = OID_ARRAY_INIT;
+	struct oid_array tagged_blob_list = OID_ARRAY_INIT;
+
 	trace2_region_enter("path-walk", "commit-walk", info->revs->repo);
 
 	CALLOC_ARRAY(commit_list, 1);
@@ -260,6 +264,60 @@ int walk_objects_by_path(struct path_walk_info *info)
 	oid_array_clear(&commit_list->oids);
 	free(commit_list);
 
+	if (info->tags) {
+		struct oid_array tags = OID_ARRAY_INIT;
+
+		trace2_region_enter("path-walk", "tag-walk", info->revs->repo);
+
+		/*
+		 * Walk any pending objects at this point, but they should only
+		 * be tags.
+		 */
+		for (size_t i = 0; i < info->revs->pending.nr; i++) {
+			struct object_array_entry *pending = info->revs->pending.objects + i;
+			struct object *obj = pending->item;
+
+			while (obj->type == OBJ_TAG) {
+				struct tag *tag = lookup_tag(info->revs->repo,
+							     &obj->oid);
+				oid_array_append(&tags, &obj->oid);
+				obj = tag->tagged;
+			}
+
+			switch (obj->type) {
+			case OBJ_TREE:
+				oid_array_append(&tagged_tree_list, &obj->oid);
+				break;
+
+			case OBJ_BLOB:
+				oid_array_append(&tagged_blob_list, &obj->oid);
+				break;
+
+			case OBJ_COMMIT:
+				/* skip */
+				break;
+
+			default:
+				BUG("should not see any other type here");
+			}
+		}
+
+		info->path_fn("initial", &tags, OBJ_TAG, info->path_fn_data);
+
+		if (tagged_tree_list.nr)
+			info->path_fn("tagged-trees", &tagged_tree_list, OBJ_TREE,
+				      info->path_fn_data);
+		if (tagged_blob_list.nr)
+			info->path_fn("tagged-blobs", &tagged_blob_list, OBJ_BLOB,
+				      info->path_fn_data);
+
+		trace2_data_intmax("path-walk", ctx.repo, "tags", tags.nr);
+		trace2_region_leave("path-walk", "tag-walk", info->revs->repo);
+		oid_array_clear(&tags);
+		oid_array_clear(&tagged_tree_list);
+		oid_array_clear(&tagged_blob_list);
+	}
+
 	string_list_append(&ctx.path_stack, root_path);
 
 	trace2_region_enter("path-walk", "path-walk", info->revs->repo);
diff --git a/path-walk.h b/path-walk.h
index 49b982dade6..637d3b0cabb 100644
--- a/path-walk.h
+++ b/path-walk.h
@@ -39,6 +39,7 @@ struct path_walk_info {
 	int commits;
 	int trees;
 	int blobs;
+	int tags;
 
 	/**
 	 * Specify a sparse-checkout definition to match our paths to. Do not
-- 
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